Application of Single-Site Catalysts in the Hydrogen Economy

Hydrogen is an ideal alternative, clean fuel to replace traditional fossil fuels due to its high mass energy density and natural abundance. To meet the hydrogen demands of industry and daily life, it is vital to seek a low-cost and efficient catalyst to produce hydrogen from hydrogen-containing molecules. Single-site catalysts, a relatively new generation of materials, potentially provide high efficiency and maximum atom utilization in hydrogen generation reactions. Catalysts development is an evolutionary process. The generation of new single-metal-site catalysts, with isolated metal atoms dispersed on the surface of substrates, offers maximum atom-utilization efficiency, high specific activity, and novel properties. The unique structure of single-site catalysts also enables their potential to bridge the gap between homogeneous and heterogeneous catalysis. This field is at an early stage, characterized by important discoveries and novel demonstrations of catalytic properties associated with the fine structure of single metal sites; however, specific applications, especially catalytic hydrogenation reactions, are still lacking. The focus of this short review is on applications of single-site catalysts in the hydrogen economy based on our studies of hydrogen generation/storage via single-metal-site catalysts. We hope this work will inspire the development of single-site catalysts for other applications. Catalysts development is an evolutionary process. The generation of new single-metal-site catalysts, with isolated metal atoms dispersed on the surface of substrates, offers maximum atom-utilization efficiency, high specific activity, and novel properties. The unique structure of single-site catalysts also enables their potential to bridge the gap between homogeneous and heterogeneous catalysis. This field is at an early stage, characterized by important discoveries and novel demonstrations of catalytic properties associated with the fine structure of single metal sites; however, specific applications, especially catalytic hydrogenation reactions, are still lacking. The focus of this short review is on applications of single-site catalysts in the hydrogen economy based on our studies of hydrogen generation/storage via single-metal-site catalysts. We hope this work will inspire the development of single-site catalysts for other applications. a method to apply AA to pre-produce the support and further apply the support to reduce metal precursors. the carrying down by a precipitate of substances normally soluble under the conditions used. small amounts of isolated metal atoms are present in the surface layer of a metal host. a catalyst that contains definite, uniform, and isolated active sites. method for producing syngas (hydrogen and carbon monoxide) by the reaction of methane with water, CH4 + H2O = CO + 3H2.